3ders.org, 12 July 2013
http://www.3ders.org/articles/20130712-nasa-hot-fire-tests-3d-printed-rocket-injector.html
NASA and Aerojet Rocketdyne recently finished testing a rocket engine injector made through additive manufacturing, or 3D printing. What you see below is the liquid oxygen/gaseous hydrogen rocket injector assembly built using 3D printing technology being hot-fire tested at NASA Glenn Research Center's Rocket Combustion Laboratory in Cleveland.